Field of the Invention
The present invention relates to a control device for a transmission of a vehicle, and in particular, a control device for learning a synchronizer balk position in a dual clutch type transmission including two shift shafts for odd- and even-numbered shift gears and a shift gear mechanism related thereto. The present invention further relates to a learning method for the synchronizer balk position.
Description of the Related Art
Japanese Patent Application Publication No. 2005-42798 (Patent Document 1) discloses an art for learning and storing a balk position (balk point) of a synchronizer (namely, synchromesh mechanism) beforehand for switching shift gears in a transmission gear train provided between an input shaft and an output shaft mutually parallel to each other to be used for stroke control of a sleeve. The balk position (balk point) is a position at which a synchronous sleeve contacts with a synchronizer ring in the process of sliding (shifting) of the sleeve. At this contact position, the sleeve stops to move for an instant, thereby allowing to confirm (learn) this balk position. If a balk position (balk point) is learned beforehand for every individual synchronizer, effective synchronous control can be performed by, for example, switching driving force of an actuator for sliding the synchronous sleeve when the synchronous sleeve reaches the balk position in operation of the actuator. As every individual synchronizer has its own balk position due to its individual differences, such balk position learning is indispensable before factory shipment of the transmission or at the time of maintenance. It should be noted that at the time of balk position learning, a difference between input and output rotations of the synchronizer needs to be kept constant.
On the other hand, a dual clutch type transmission including two shift shafts for odd- and even-numbered shift gears and a shift gear mechanism related thereto is also known (for example, refer to International Publication WO2010/046307 (Patent Document 2)). In such dual clutch type transmission, a first shift gear mechanism is installed between a first input shaft, detachably connected via a first clutch to a power source (for example, internal-combustion engine), and an output shaft (counter shaft). Also, a second shift gear mechanism is installed between a second input shaft, detachably connected via a second clutch to the power source, and the output shaft (counter shaft). Shift gears in the first and second shift gear mechanisms are switched/selected using synchronizers installed so as to correspond to the shift gears.
Conventionally, in such dual clutch type transmission, the synchronizer balk position learning is conducted by setting the rotation speed of the output shaft (counter shaft) at 0 with the brake on, and with the first or second clutch on. For example, in the case of synchronizer balk position learning for an odd-numbered shift gear, the difference between the input and output rotations of the synchronizer is kept constant by turning on the brake and the first clutch (or the input and output rotations of the synchronizer are kept respectively at the engine speed and 0), and then the sleeve is slid. In the case of synchronizer balk position learning for an even-numbered shift gear, the difference between the input and output rotations of the synchronizer is kept constant by turning on the brake and the second clutch (or the input and output rotations of the synchronizer are kept respectively at the engine speed and 0), and then the sleeve is slid.